This invention relates to a solid electrolytic capacitor and a transmission line device both of which is applicable to various fields such as a noise filter or a smoothing device and, in particular, to a laminated solid electrolytic capacitor comprising a plurality of solid electrolytic capacitor elements integrally laminated onto one another and a laminated transmission line device comprising a plurality of transmission line elements integrally laminated onto one another.
This kind of laminated solid electrolytic capacitor comprises a plurality of solid electrolytic capacitor elements. The solid electrolytic capacitor elements are provided with an anode body, a dielectric layer, and a cathode body, respectively. The dielectric layer is served by an oxidized film formed on the anode body. Alternatively, this kind of laminated transmission line device is like in structure to the laminated solid electrolytic capacitor mentioned above. Namely, the laminated transmission line device comprises a plurality of transmission line elements. The transmission line elements are also provided with an anode body, a dielectric layer, and a cathode body, respectively. The dielectric layer is served by an oxidized film formed on the anode body.
Generally, it is requested for the laminated solid electrolytic capacitor and the laminated transmission line device to have large capacity and low impedance. It is effective to increase the capacity and to reduce the impedance of the laminated solid electrolytic capacitor or the laminated transmission line device that the number of the solid electrolytic capacitor element or the transmission line element is increased. However, because the size of the impedance of the laminated solid electrolytic capacitor or the laminated transmission line device is increased, it is not preferred only that the number of the solid electrolytic capacitor element or the transmission line element is increased. In order to satisfy both to increase the capacity and to reduce the impedance, it is useful to laminate the solid electrolytic capacitor elements or the transmission line elements onto one another in a thickness direction of the elements.
As an example in which the solid electrolytic capacitor elements are laminated onto one another in the thickness direction, a laminated solid electrolytic capacitor comprising two solid electrolytic capacitor elements laminated to each other is disclosed in Japanese Patent Application Publication (JP-A) No. H11-135367. In the existing laminated solid electrolytic capacitor, cathode bodies of the solid electrolytic capacitor elements are connected to each other by electrically conductive adhesive. End regions of anode bodies of the solid electrolytic capacitor elements are jointed to a lead frame by welding. When the end regions are jointed to the lead frame, the end regions of the anode bodies each of which has a straight shape are pressed in a direction so as to close in with each other. Therefore, each of the end regions are deformed (bent) into a stepwise shape.
In the existing laminated solid electrolytic capacitor, because the end regions of the anode bodies are deformed (bent) when the end regions are jointed to the lead frame, stress caused by the deforming may be reached each of the cathode bodies which have been formed on each of the anode bodies. If large stress is impressed on the cathode body, an oxidized film as a dielectric layer formed between the anode body and the cathode body is damaged. Therefore, the solid electrolytic capacitor element is deteriorated in performance. Particularly, when many solid electrolytic capacitor elements are laminated, the more the solid electrolytic capacitor element is laminated at peripheral layer, the more the anode body is deformed. Therefore, when many solid electrolytic capacitor elements are laminated, a possibility that the performance of the solid electrolytic capacitor elements is deteriorated becomes higher. Therefore, in the existing laminated solid electrolytic capacitor, a limit on the number of the solid electrolytic capacitor elements laminated was practically two. There is also such disadvantage in the transmission line elements of the laminated transmission line device like to the solid electrolytic capacitor elements in structure.
Such as a laminated solid electrolytic capacitor or a laminated transmission line device laminated is also disclosed in the copending U.S. patent application Ser. No. 10/779,025 filed on Feb. 13, 2004 by the present applicants.